Hi. Have two fermenters with beer brewing. I brewed over the weekend, and started increasing the temperature yesterday (I usually start on day 3 or 4). Ambient water temp was at 70 degrees. The yeasts are: WLP005 and WLP085. The 005 is for an Imperial Stout that I wanted to coax to 10% ABV or more. The 085 is a Brown Ale that is usually around 6%. Today there was a 6-hr power outage. The ambient temp got to 56 degrees, so the beer was probably right around there too. I know yeast are pretty resilient, but dropping 13 degrees in 6 hrs is a pretty large swing over a short time; followed by however many hours to get back up to temp. I know I'll have beer, but do you think the yeast will ramp back up? What can I do to help encourage them? (I'm thinking that when it gets back to fermenting temp, kind of rouse them a little by agitating the fermenters or stirring the beer a little). Thanks for your thoughts.
I think you answered your own question. Rouse those puppies after the temp is back up. Don't forget to sanitize your spoon first.
I had a somewhat similar situation just a few days ago. I pitched yeast at 62 degrees and my temp control malfunctioned, with the wort cooling to the mid 30s overnight in 12-15 hours. I got the temp back up over the course of the next day and fermentation started at 58 degrees about 24 hours later. The next morning, the yeast were ripping through the beer as expected and things seem to be on track. I agree with stirring or gentle sloshing. I sloshed without concern for oxidation but that was < 1 day after pitching.
Thanks guys. I know to RAHAHB, but I still want to plan ahead. I figured if the temp dropped early in fermentation it would be less an issue. But so late, when the yeast are nearing the end, it would be a bigger issue. I'll give them a whirl with a (sanitized) spoon. The aquarium heater heats pretty quick, so hopefully the yeast will feel like they just had a short nap and get right back to it. Cheers!
If the power was only out for 6 hours and the ambient air temperature was 56F I doubt the liquid temperature dropped more than a few degrees during that time unless these were very small batches. That's not a large temperature differential between the air and liquid and it takes a lot of energy to raise/lower the temperature of water based liquids by a degree.
They're 5 gallon batches in 7 gallon fermenting buckets. I have no doubt the temps decreased to 56 degrees. I have a few lids that, in addition to the airlock, I put a hole in with a rubber stopper with a long thermometer in them. The temp difference of the beer and ambient water was never more than a few degrees except during peak fermentation, then it was about 5 degrees at the most. Still. I'm going to have faith in the resilience of the yeast, I'll "sacrifice" a couple home brews to my liver, and hope for the best.
